Download the latest Windows installer for your system . Extract it to a path owned by your user account (e.g. your Desktop). Run the included bin\quetoo-update.exe. This may take a few minutes the first time you run it, but it will take significantly less time on subsequent runs. You should run quetoo-update often. When the updater finishes, you can close the console window and run bin\quetoo.exe.
Download the latest Mac installer, open it, and drag the Quetoo folder onto the Applications shortcut. From your Applications folder, click the Quetoo folder and run Update.app. This may take a few minutes the first time you run it, but it will take significantly less time on subsequent runs. When Update.app finishes, you can close the Terminal window and then run Quetoo.app. You should run Update.app often.
Download the latest GNU / Linux installer, and extract the tarball to a location of your choosing (e.g.
/opt/quetoo, etc). Run
bin/quetoo-update to install the latest game data and binaries. This may take a few minutes, but will be faster on subsequent runs. When the updater is completed, you can launch Quetoo by double-clicking